Researchers split 100 patients with heart failure into two groups: Half participated in a 12-week tai chi program, while the others spent 12 weeks in an educational program learning about heart-related issues, like low-sodium diets and heart-rhythm problems. At the end of the study, the tai chi group reported improvements in mood, less depression, less fatigue, and more energy than the others—and those in the first group were more likely to continue with some type of physical activity, according to findings published Monday in the Archives of Internal Medicine. ”Maintaining an exercise regimen is important in heart failure,” study author Gloria Yeh of Beth Israel Deaconess Medical Centertold HealthDay. ”Tai chi may be a suitable alternative or adjunct exercise for these patients.”

Perhaps it’s a testament to the power of yoga that so many spin-offs have emerged—dozens since it originated some 6,000 years ago. There’s laughter yoga, which turns humor into a healing power, AcroYoga, which revolves around flying, and hot yoga, taught in a 105-degree studio. Even naked yoga is catching on, described by followers as a therapeutic way to burst out of the confines of clothing.

Research bolsters the claims made for the trend: Yoga protects the brain from depression, an August study found; three sessions per week boosted participants’ levels of the brain chemical GABA, which typically translates into improved mood and decreased anxiety. ”People who have disorders like depression and anxiety can definitely benefit from yoga, because it returns [GABA] levels to the normal range,” says study author Chris Streeter, an assistant professor of psychiatry and neurology at Boston University School of Medicine. Streeter says yoga can be used to complement—not substitute—drug treatment for depression.

Past research has explored yoga’s effect on epilepsy, heart disease, cancer, and multiple sclerosis, among other conditions. A 2004 Yale University School of Medicine study, for instance, found that people who practice yoga reduced their blood pressure, pulse, and risk of heart disease. The health benefits likely come about—at least in large part—because yoga helps people better manage stress, says Janice Kiecolt-Glaser, a professor with the Institute for Behavioral Medicine Research at Ohio State University College of Medicine. ”Yoga has a meditation component that is not true of other exercise. That aspect makes a difference,” she says. [Read more: Benefits of Yoga: How Different Types Affect Health.]

The gentle, 2,000-year-old Chinese practice of tai chi is often described as ”meditation in motion.” But the Harvard Women’s Health Watch newsletter suggests a more apt description is ”medication in motion.”

Tai chi, the most famous branch of Qigong, or exercises that harness the qi (life energy, pronounced ”chee”), has been linked to health benefits for virtually everyone from children to seniors. Researchers aren’t sure exactly how, but studies show that tai chi improves the quality of life for breast cancer patients and Parkinson’s sufferers. Its combination of martial artsmovements and deep breathing can be adapted even for people in wheelchairs. And it has shown promise in treating sleep problems and high blood pressure.

Tai chi is credited with so many pluses, physiological and psychological, that Chenchen Wang, an associate professor of medicine at Tufts University, set out in 2009 to analyze 40 studies on it in English and Chinese journals. Wang found that tai chi did indeed promote balance, flexibility, cardiovascular fitness, and strength. In a study comparing it with brisk walking and resistance training, a tai chi group improved more than 30 percent in lower-body strength and 25 percent in arm strength, nearly as much as a weight-training group and more than the walkers. [Read more: For Health Benefits, Try Tai Chi.]